I found it in a Half Price Books back in 2000. One of the best gaming buys I ever made.
On a tangent, I'm hoping that Hero Games gets Ken Hite to author Horror Hero (due in 2006). Given his friendship with the company and positive feelings for their products, I'm thinking it's a distinct possibility.
Another good set of horror advice was the original ravenloft boxed set that came out in 2e. I think it is available as a pdf at www.rpgnow.com . I have not been as impressed by the horror advice in followup ravenloft ones though. GURPS horror was OK as well.